CAIRO, Egypt, Sept. 29 — Gaston Maspero, the first director of Egypt’s national storehouse of ancient treasures, is said to have believed his museum should resemble pharaohs’ tombs — crowded with paintings and statues, furniture and jewelry. One hundred years after the Egyptian Museum opened, its basement, at least, is everything the French Egyptologist could have hoped for. Wandering through its shadowy maze is like exploring the inside of a pyramid.